Windshields for vehicles are generally disposed in a stack supported on and secured to a rack so as to permit handling, storage and shipment, such as from the windshield manufacturer to the vehicle assembler. The windshields are normally oriented such that the elongate direction thereof projects upwardly so that the windshield is supported by its lower edge on a rack, and a plurality of such windshields are then disposed in closely adjacent relationship to one another on the rack so as to form a substantially horizontally-extending stack. The stack of windshields is secured to the rack by any conventional means, such as by banding straps.
To protect the adjacent windshields when they are stacked and strapped on the rack, it has been conventional to provide packaging separators of a plastic foam disposed between the adjacent windshields. For example, one conventional packaging separator which has been extensively utilized for this purpose involves a sheet-like packaging member formed from a thin sheet of a rigid beaded polystyrene foam. This known packaging separator is conventionally of substantial size, such as having a width dimension of about 30 inches, a length dimension of about 30 inches, and a thickness of about 1/4 inch.
While this known packaging separator is highly effective in providing proper but minimal clearance between adjacent windshields so as to permit packaging and shipping thereof, and also ease of removal of the windshields when use is desired at the vehicle assembler, nevertheless this known separator possesses features which have been less than desirable. Most specifically, this known separator is costly because of its size and the quantity of plastic material required. The size of this separator also creates additional disadvantages with respect to storing, handling and disposing of the separators.
In an attempt to overcome many of the disadvantages associated with the known separator described above, the Applicant previously proposed a separator which was of substantially smaller size so as to significantly reduce the storing, handling and disposing problems, and which was also of significantly less material so as to reduce the cost. This reduced-size separator has a length of about 30 inches, a thickness in the order of about 1/4 inch, but a width of only about 1 inch. This proposed separator is defined by a narrow elongate strip of rigid plastic foam having generally parallel opposed side surfaces and, as shown in FIG. 6, one of these side surfaces has two small and spaced patches or strips of highly-plasticized polyvinyl chloride (PVC) foam patches adhered to one side thereof so as to project outwardly from the one-side of the rigid layer. With this arrangement, however, it was discovered that use of beaded polystyrene foam was less than optimum since the smaller size of the rigid board prevented it from possessing the desired strength necessary for removal, and hence breakage readily occurred. To improved thereon, the rigid foam board was extruded of polystyrene foam so as to provide a dense outside skin. This does provide a significantly improved strength. Even with this improvement, however, it was observed that the packaging separator became too tightly bonded to the windshield and could not be separated from the windshield without breakage of the separator. More specifically, the PVC foam patches almost totally flattened when the separator was positioned between adjacent windshields and the windshields were banded together. This substantially total flattening of the PVC foam patches, due to their very small area and the fact that they constituted the primary pressure-transfer area between the windshield and the rigid board, resulted in extremely high pressure between the windshield and the PVC foam patches. This high pressure created such a high adhesion of the patch to the windshield that, when it was desired to separate the windshields and remove the separators, the separators could not be readily detached from the windshield.
Accordingly, the present invention relates to an improved packaging separator which is believed to overcome the many problems and disadvantages which have been briefly summarized above.
In the improved packaging separator of the present invention, the separator is formed primarily by a rigid foam backing sheet which is normally rather thin and has generally parallel side surfaces. A shallow recess or depression is formed inwardly from one of the side surfaces of the rigid backing sheet, this recess being defined by a bottom wall or surface which is generally parallel with but located between the side surfaces of the backing sheet. A thin layer of an adhering plastic foam, such as a highly-plasticized PVC foam pad, is positioned within the recess so that the back surface of this PVC foam pad is adhered to the bottom wall of the recess. This PVC foam pad has a thickness which exceeds the depth of the recess so that it projects outwardly of the recess beyond the side surface of the backing sheet, whereby the PVC foam pad has an exposed surface adapted for contacting an object, such as a windshield, which is spaced outwardly from the adjacent side surface of the backing sheet when the pad is in a noncompressed condition. When the packaging separator is located between two objects such as windshield, this PVC foam pad is initially contacted by the one windshield and compressed until the backing sheet also comes into contact with the same windshield, whereby the contact pressure is then distributed over the complete surface area of the packaging separator. The permissible compression of the PVC foam pad is thus limited in that it cannot be compressed to a substantially flatten condition in view of its being positioned within the shallow recess. This thus controls the adhesive or gripping pressure which exists between the foam pad and the windshield, and facilitates the separation of the windshields and the ultimate removal of the packaging separators.
The packaging separator of the present invention, as briefly summarized above, when used to permit stacking or packaging of windshields, preferably has the backing sheet formed as a elongate strip, such as having width and length dimensions of about 1 inch and 30 inches respectively, and prefereably has two shallow recessed formed therein spaced longitudinally therealong so that each recess in turn accommodates a PVC foam pad, the pad typically having length and width dimensions of about 1 inch by 1 inch.
The improved packaging separator is particularly advantageous in that it can be inexpensively manufactured since it requires use of a minimal quantity of plastics material, and it can also be economically and compactly stored, handled and ultimately disposed of because of its extremely small and compact size.
Other objects and purposes of the invention will be apparent to persons familiar with structures of this general type upon reading the following specification and inspecting the accompanying drawings.